I already did a archived searched for this: what is the normal operating temperature for an H23 engine. My friends Prelude oil and coolant temp seems to run 210 degrees F. I would think it is normal but steam comes from under his hood. Any help will be appreciated.

 

You've got a leak in the cooling system somewhere or there could be no syeam unless its from teh radiator cap and then that means your overheating for some reason and it's venting. Sooner or later you will blow a hose apart and over heat. The normal thermostat is like 195 degrees and the cooler one (which I run) is 180 degrees. Try that but 210 is not out of the question at all if the 195 degree thermostat is in there which it probably is. Is the in car temp gauge ever above half way? If not your fine.